S
M
T
W
T
F
S
30
74°
57°
31
76°
55°
1
76°
60°
2
76°
59°
3
80°
65°
4
76°
64°
5
69°
57°
6
73°
56°
7
80°
63°
8
73°
60°
9
71°
59°
10
72°
55°
11
66°
51°
12
75°
53°
13
78°
63°
14
66°
49°
15
65°
48°
16
77°
61°
17
70°
58°
18
68°
45°
19
61°
48°
20
64°
48°
21
62°
47°
22
62°
46°
23
65°
51°
24
66°
54°
25
65°
53°
26
69°
52°
27
65°
53°
28
66°
51°
29
65°
55°
30
67°
53°
1
63°
35°
2
59°
41°
3
59°
47°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
September Weather in Montreal
Montreal's September 2026 forecast shows daily high temperatures ranging from 59° to 69°, with overnight lows between 35° and 55°. The average high for September is 64° with an average low of 49°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how September weather will actually feel in Montreal. See also: October | November | December.
